The present invention relates to a process for the preparation of a composition comprising tartaric acid wherein between 55 and 90% by weight of the tartaric acid is meso-tartaric acid, comprising the steps of (i) preparing an aqueous mixture comprising between 35 and 65% by weight of a di-alkali metal salt of L-tartaric acid, a di-alkali metal salt of D-tartaric acid, a mixture of di-alkali metal salts of L-tartaric acid, D-tartaric acid, and optionally meso-tartaric acid, and between 2 and 15% by weight of an alkali metal or alkaline metal hydroxide, and (ii) stirring and heating the aqueous mixture to a temperature of between 100° C. and its boiling point until between 55 and 90% by weight of tartaric acid has been converted to meso-tartaric acid.